Tempest Wolves are one of the evolved forms of Direwolves, adopting the "storm" element.
When Rimuru gave Ranga a name, it triggered a piece of Demon Essence. Unlike his father, Ranga believes in the concept of "All for One." As a result, his fellow wolves also evolved into Tempest Wolves.
Direwolves weren’t really supposed to evolve toward the “storm” element in the first place—that was just a side effect of the name Rimuru gave out.
Tempest Wolves have jet black fur, which gives a feeling of bewitching gloss and a glossy finish. The tempest element gave the wolf pack an ever-so-slight purplish shine to their black color. Furthermore, their length is nearly 3m.
They are fast and don't show any fatigue. They can run for 3 hour at 80 km without taking a break.